The motor cools down through air intakes and air outlets in the base of the machine. It is important that these are kept free. The machine can switch itself off if it is subjected to a very high load. The digital overload protection switches it off. This is controlled by a digital motor control with speed feedback. Set the machine to “Off”, and start again. If the machine is subjected to heavy loads, one way to deal with this is to increase the speed slightly.
The machine can also switch itself off if the heat sensor detects that the motor has got too hot. The machine then needs to rest a while before it can be used again. If you have been running large volumes in it, with quite a lot of resistance, you need to switch the machine off and wait for a few minutes.